PGE2 inhibits TIL expansion by disrupting IL-2 signalling and mitochondrial function.

Expansion of antigen-experienced CD8+ T cells is critical for the success of tumour-infiltrating lymphocyte (TIL)-adoptive cell therapy (ACT) in patients with cancer1. Interleukin-2 (IL-2) acts as a key regulator of CD8+ cytotoxic T lymphocyte functions by promoting expansion and cytotoxic capability2,3. Therefore, it is essential to comprehend mechanistic barriers to IL-2 sensing in the tumour microenvironment to implement strategies to reinvigorate IL-2 responsiveness and T cell antitumour responses. Here we report that prostaglandin E2 (PGE2), a known negative regulator of immune response in the tumour microenvironment4,5, is present at high concentrations in tumour tissue from patients and leads to impaired IL-2 sensing in human CD8+ TILs via the PGE2 receptors EP2 and EP4. Mechanistically, PGE2 inhibits IL-2 sensing in TILs by downregulating the IL-2Rγc chain, resulting in defective assembly of IL-2Rß-IL2Rγc membrane dimers. This results in impaired IL-2-mTOR adaptation and PGC1α transcriptional repression, causing oxidative stress and ferroptotic cell death in tumour-reactive TILs. Inhibition of PGE2 signalling to EP2 and EP4 during TIL expansion for ACT resulted in increased IL-2 sensing, leading to enhanced proliferation of tumour-reactive TILs and enhanced tumour control once the cells were transferred in vivo. Our study reveals fundamental features that underlie impairment of human TILs mediated by PGE2 in the tumour microenvironment. These findings have therapeutic implications for cancer immunotherapy and cell therapy, and enable the development of targeted strategies to enhance IL-2 sensing and amplify the IL-2 response in TILs, thereby promoting the expansion of effector T cells with enhanced therapeutic potential.

A miRNA-7704/IL2RB/AKT feedback loop regulates tumorigenesis and chemoresistance in ovarian cancer.

Ovarian cancer is one of the most common gynecological tumors worldwide. Despite the availability of multiple treatments for ovarian cancer, its resistance to chemotherapy remains a significant challenge. miRNAs play crucial roles in the initiation and progression of cancer by affecting processes such as differentiation, proliferation, and chemoresistance. According to microarray and qPCR analyses, miR-7704 is significantly downregulated in cisplatin-resistant cells compared to parental cells. In this study, we found that miR-7704 inhibited the proliferation and promoted cisplatin sensitivity of ovarian cancer cells in vitro and in vivo. Moreover, ectopic expression of miR-7704 had the same effect as IL2RB knockdown. Further mechanistic studies revealed that miR-7704 played an inhibitory role by regulating IL2RB expression to inactivate the AKT signaling pathway. Furthermore, IL2RB reversed the miR-7704 mediated resistance to cisplatin in ovarian cancer. Based on these findings, miR-7704 and IL2RB show the potential as novel therapeutic targets for ovarian cancer.

CSF1R blockade slows progression of cerebral hemorrhage by reducing microglial proliferation and increasing infiltration of CD8 + CD122+ T cells into the brain.

Microglia play a pivotal role in the neuroinflammatory response after brain injury, and their proliferation is dependent on colony-stimulating factors. In the present study, we investigated the effect of inhibiting microglia proliferation on neurological damage post intracerebral hemorrhage (ICH) in a mouse model, an aspect that has never been studied before. Using a colony-stimulating factor-1 receptor antagonist (GW2580), we observed that inhibition of microglia proliferation significantly ameliorated neurobehavioral deficits, attenuated cerebral edema, and reduced hematoma volume after ICH. This intervention was associated with a decrease in pro-inflammatory factors in microglia and an increased infiltration of peripheral regulatory CD8 + CD122+ T cells into the injured brain tissue. The CXCR3/CXCL10 axis is the mechanism of brain homing of regulatory CD8 + CD122+ T cells, and the high expression of IL-10 is the hallmark of their synergistic anti-inflammatory effect with microglia. And activated astrocytes around the insult site are a prominent source of CXCL10. Thus, inhibition of microglial proliferation offers a new perspective for clinical translation. The cross-talk between multiple cells involved in the regulation of the inflammatory response highlights the comprehensive nature of neuroimmunomodulation.

MK-6, a novel not-α IL-2, elicits a potent antitumor activity by improving the effector to regulatory T cell balance.

IL-2 is a pleiotropic cytokine that regulates immune cell homeostasis. Its immunomodulatory function has been used clinically as an active immunotherapy agent for metastatic cancers. However, severe adverse effects, including the vascular leak syndrome and the preferential stimulation of anti-immunogenic Treg rather than effector T cells, have been obstacles. We newly designed a mutein IL-2, Mutakine-6 (MK-6), with reduced IL-2Rα-binding capability. MK-6 induced comparable cell growth potential toward IL-2Rßγ-positive T cells but was far less efficient in in vitro Treg proliferation and STAT5 activation. Unlike IL-2, in vivo administration of MK-6 produced minimal adverse effects. Using CT26 and B16F10-syngeneic tumor models, we found MK-6 was highly efficacious on tumor regression. Serum albumin conjugation to MK-6 prolonged in vivo half-life and accumulated in CT26 tumors, showing enhanced antitumor effect. Tumor-infiltrating leukocytes analysis revealed that albumin-fused MK-6 increased the ratio of effector CD8+ T cells to CD4+ Treg cells. These results demonstrated that MK-6 is an efficient immunomodulator potentially used for improved immunotherapy with decreased adverse effects and attenuated Treg stimulation.

Development of Stable Chimeric IL-15 for Trans-Presentation by the Antigen Presenting Cells.

IL-15 is one of the important biologics considered for vaccine adjuvant and treatment of cancer. However, a short half-life and poor bioavailability limit its therapeutic potential. Herein, we have structured IL-15 into a chimeric protein to improve its half-life enabling greater bioavailability for longer periods. We have covalently linked IL-15 with IgG2 base to make the IL-15 a stable chimeric protein, which also increased its serum half-life by 40 fold. The dimeric structure of this kind of IgG based biologics has greater stability, resistance to proteolytic cleavage, and less frequent dosing schedule with minimum dosage for achieving the desired response compared to that of their monomeric forms. The structured chimeric IL-15 naturally forms a dimer, and retains its affinity for binding to its receptor, IL-15Rß. Moreover, with the focused action of the structured chimeric IL-15, antigen-presenting cells (APC) would transpresent chimeric IL-15 along with antigen to the T cell, that will help the generation of quantitatively and qualitatively better antigen-specific memory T cells. In vitro and in vivo studies demonstrate the biological activity of chimeric IL-15 with respect to its ability to induce IL-15 signaling and modulating CD8+ T cell response in favor of memory generation. Thus, a longer half-life, dimeric nature, and anticipated focused transpresentation by APCs to the T cells will make chimeric IL-15 a super-agonist for memory CD8+ T cell responses.

Downregulation of miR-497-5p Improves Sepsis-Induced Acute Lung Injury by Targeting IL2RB.

INTRODUCTION: Acute lung injury (ALI) induced by sepsis is a process related to inflammatory reactions, which involves lung cell apoptosis and production of inflammatory cytokine. Here, lipopolysaccharide (LPS) was applied to stimulate the mouse or human normal lung epithelial cell line (BEAS-2B) to construct a sepsis model in vivo and in vitro, and we also investigated the effect of miR-497-5p on sepsis-induced ALI. Material and Methods. Before LPS treatment, miR-497-5p antagomir was injected intravenously into mice to inhibit miR-497-5p expression in vivo. Similarly, miR-497-5p was knocked down in BEAS-2B cells. Luciferase reporter assay was applied to predict and confirm the miR-497-5p target gene. Cell viability, apoptosis, the levels of miR-497-5p, IL2RB, SP1, inflammatory cytokine, and lung injury were assessed. RESULTS: In BEAS-2B cells, a significant increase of apoptosis and inflammatory cytokine was shown after LPS stimulation. In septic mice, increased inflammatory cytokine production and apoptosis in lung cells and pulmonary morphological abnormalities were shown. The miR-497-5p inhibitor transfection showed antiapoptotic and anti-inflammatory effects on BEAS-2B cells upon LPS stimulation. In septic mice, the miR-497-5p antagomir injection also alleviated ALI, apoptosis, and inflammation caused by sepsis. The downregulation of IL2RB in BEAS-2B cells reversed the protective effects of the miR-497-5p inhibitor against ALI. CONCLUSION: In conclusion, downregulation of miR-497-5p reduced ALI caused by sepsis through targeting IL2RB, indicating the potential effect of miR-497-5p for improving ALI caused by sepsis.

TREM2 promotes natural killer cell development in CD3-CD122+NK1.1+ pNK cells.

BACKGROUND: Triggering receptor expressed on myeloid cells 2 (TREM2) signaling is considered to regulate anti-inflammatory responses in macrophages, dendritic cell maturation, osteoclast development, induction of obesity, and Alzheimer's disease pathogenesis. However, little is known regarding the effect of TREM2 on natural killer (NK) cells. RESULTS: Here, we demonstrated for the first time that CD3-CD122+NK1.1+ precursor NK (pNK) cells expressed TREM2 and their population increased in TREM2-overexpressing transgenic (TREM2-TG) mice compared with that in female C57BL/6 J wild type (WT) mice. Both NK cell-activating receptors and NK cell-associated genes were expressed at higher levels in various tissues of TREM2-TG mice than in WT mice. In addition, bone marrow-derived hematopoietic stem cells (HSCs) of TREM2-TG mice (TG-HSCs) successfully differentiated into NK cells in vitro, with a higher yield from TG-HSCs than from WT-HSCs. In contrast, TREM2 signaling inhibition by TREM2-Ig or a phosphatidylinositol 3-kinase (PI3K) inhibitor affected the expression of the NK cell receptor repertoire and decreased the expression levels of NK cell-associated genes, resulting in significant impairment of NK cell differentiation. Moreover, in melanoma-bearing WT mice, injection of bone marrow cells from TREM2-TG mice exerted greater antitumor effects than that with cells from WT control mice. CONCLUSIONS: Collectively, our data clearly showed that TREM2 promoted NK cell development and tumor regression, suggesting TREM2 as a new candidate for cancer immunotherapy.

SLFN2 protection of tRNAs from stress-induced cleavage is essential for T cell-mediated immunity.

Reactive oxygen species (ROS) increase in activated T cells because of metabolic activity induced to support T cell proliferation and differentiation. We show that these ROS trigger an oxidative stress response that leads to translation repression. This response is countered by Schlafen 2 (SLFN2), which directly binds transfer RNAs (tRNAs) to protect them from cleavage by the ribonuclease angiogenin. T cell-specific SLFN2 deficiency results in the accumulation of tRNA fragments, which inhibit translation and promote stress-granule formation. Interleukin-2 receptor ß (IL-2Rß) and IL-2Rγ fail to be translationally up-regulated after T cell receptor stimulation, rendering SLFN2-deficient T cells insensitive to interleukin-2's mitogenic effects. SLFN2 confers resistance against the ROS-mediated translation-inhibitory effects of oxidative stress normally induced by T cell activation, permitting the robust protein synthesis necessary for T cell expansion and immunity.

CD122-directed interleukin-2 treatment mechanisms in bladder cancer differ from αPD-L1 and include tissue-selective γδ T cell activation.

BACKGROUND: Anti-programmed death-ligand 1 (αPD-L1) immunotherapy is approved to treat bladder cancer (BC) but is effective in <30% of patients. Interleukin (IL)-2/αIL-2 complexes (IL-2c) that preferentially target IL-2 receptor ß (CD122) augment CD8+ antitumor T cells known to improve αPD-L1 efficacy. We hypothesized that the tumor microenvironment, including local immune cells in primary versus metastatic BC, differentially affects immunotherapy responses and that IL-2c effects could differ from, and thus complement αPD-L1. METHODS: We studied mechanisms of IL-2c and αPD-L1 efficacy using PD-L1+ mouse BC cell lines MB49 and MBT-2 in orthotopic (bladder) and metastatic (lung) sites. RESULTS: IL-2c reduced orthotopic tumor burden and extended survival in MB49 and MBT-2 BC models, similar to αPD-L1. Using antibody-mediated cell depletions and genetically T cell-deficient mice, we unexpectedly found that CD8+ T cells were not necessary for IL-2c efficacy against tumors in bladder, whereas γδ T cells, not reported to contribute to αPD-L1 efficacy, were indispensable for IL-2c efficacy there. αPD-L1 responsiveness in bladder required conventional T cells as expected, but not γδ T cells, altogether defining distinct mechanisms for IL-2c and αPD-L1 efficacy. γδ T cells did not improve IL-2c treatment of subcutaneously challenged BC or orthotopic (peritoneal) ovarian cancer, consistent with tissue-specific and/or tumor-specific γδ T cell contributions to IL-2c efficacy. IL-2c significantly altered bladder intratumoral γδ T cell content, activation status, and specific γδ T cell subsets with antitumor or protumor effector functions. Neither IL-2c nor αPD-L1 alone treated lung metastatic MB49 or MBT-2 BC, but their combination improved survival in both models. Combination treatment efficacy in lungs required CD8+ T cells but not γδ T cells. CONCLUSIONS: Mechanistic insights into differential IL-2c and αPD-L1 treatment and tissue-dependent effects could help develop rational combination treatment strategies to improve treatment efficacy in distinct cancers. These studies also provide insights into γδ T cell contributions to immunotherapy in bladder and engagement of adaptive immunity by IL-2c plus αPD-L1 to treat refractory lung metastases.

Nicotine exhausts CD8+ T cells against tumor cells through increasing miR-629-5p to repress IL2RB-mediated granzyme B expression.

The mechanism exhausting CD8+ T cells is not completely clear against tumors. Literature has demonstrated that cigarette smoking disables the immunological activity, so we propose nicotine is able to exhaust CD8+ T cells. The CD8+ T cells from healthy volunteers with and without cigarette smoking and the capacity of CD8+ T cells against tumor cells were investigated. RNAseq was used to investigate the gene profiling expression in CD8+ T cells. Meanwhile, small RNAseq was also used to search novel microRNAs involved in the exhaustion of CD8+ T cells. The effect of nicotine exhausting CD8+ T cells was investigated in vitro and in the humanized tumor xenografts in vivo. We found that CD8+ T cells were able to reduce cell viability in lung cancer HCC827 and A549 cells, that secreted granzyme B, but CD8+ T cells from the healthy cigarette smokers lost anti-HCC827 effect. Moreover, nicotine suppressed the anti-HCC827 effect of CD8+ T cells. RNAseq revealed lower levels of IL2RB and GZMB in the exhausted CD8+ T cells. We identified that miR-629-5p was increased by nicotine, that targeted IL2RB. Transfection of miR-629-5p mimic reduced IL2RB and GZMB levels. We further validated that nicotine reduced granzyme B levels using a nuclear imaging technique, and demonstrated that nicotine exhausted peripheral blood mononuclear cells against HCC827 growth in the humanized tumor xenografts. This study demonstrated that nicotine exhausted CD8+ T cells against HCC827 cells through increasing miR-629-5p to suppress IL2RB.

Chronic shift-lag promotes NK cell ageing and impairs immunosurveillance in mice by decreasing the expression of CD122.

Long-term subjection to shift work increases the risk of cancer. The purpose of the present study was to explore the mechanism by which chronic circadian disruption impairs natural killer (NK) cell immunosurveillance. Mice were subjected to light-dark reverse every 4 days for 12 weeks to disrupt normal circadian rhythm. NK cell development and function were evaluated by flow cytometry. The mRNA and protein levels of period 1 (per1) and per2 were suppressed, while circadian locomotor output cycle kaput (CLOCK) was increased in the shifted mice, indicating successful generation of the circadian rhythm disruption mouse model. Chronic shift-lag promoted NK cell ageing, which is likely due to the reduction in Ly49 family receptor expression in shifted NK. We further studied the effects of circadian rhythm disruption on NK cell function. Chronic shift-lag inhibited NK cell secretion of granular CD107a and interferon gamma. Moreover, chronic shift-lag attenuated the clearance of MHC-I-deficient tumour cells by NK cells in vivo and promoted lung metastasis of B16F10 melanomas. Furthermore, chronic shift-lag reduced NK cell killing function, which may be due to the suppression of Eomes transcription factor expression, which inhibiting the transcription of CD122. In conclusion, our findings suggest that chronic circadian disruption attenuates NK cell cytolytic activity by decreasing the expression of CD122.

CD122-targetted IL-2 signals cause acute and selective apoptosis of B cells in Peyer's Patches.

Interleukin-2 (IL-2) has both pro- and anti-inflammatory properties that have been harnessed clinically and that are used experimentally to modulate leukocyte subsets in vivo. In mice, the bioavailability and half-life of IL-2 in vivo can be increased by complexing recombinant IL-2 with different clones of anti-IL-2 monoclonal antibodies that differentially target the cytokine to cells expressing different kinds of IL-2 receptors. While the impacts of systemic IL-2: anti-IL-2 antibody complex (IL-2C) administration are well-defined in the spleen and peripheral lymph nodes, how immune cells in the gut and gut-associated lymphoid tissues respond to IL-2C is not well characterized. Here, we analyze how major leukocyte populations in these tissues respond to IL-2C. We find that IL-2C targeting cells expressing IL-2 receptor beta cause an acute decrease in cellularity of Peyer's Patches while cell numbers in the lamina propria and intraepithelial lymphocytes are unaffected. Cell contraction in Peyer's Patches is associated with the apoptosis of multiple B cell subsets. Our results are important to consider for understanding off-target impacts of IL-2C regimes in experimental models and for considering how IL-2 may contribute to the etiology or severity of gut-associated conditions such as Crohn's Disease.

IFNs Drive Development of Novel IL-15-Responsive Macrophages.

Disruption in homeostasis of IL-15 is linked to poor maternal and fetal outcomes during pregnancy. The only cells described to respond to IL-15 at the early maternal-fetal interface have been NK cells. We now show a novel population of macrophages, evident in several organs but enriched in the uterus of mice and humans, expressing the ß-chain of the IL-15R complex (CD122) and responding to IL-15. CD122+ macrophages (CD122+Macs) are morphologic, phenotypic, and transcriptomic macrophages that can derive from bone marrow monocytes. CD122+Macs develop in the uterus and placenta with kinetics that mirror IFN activity at the maternal-fetal interface. M-CSF permits macrophages to express CD122, and IFNs are sufficient to drive expression of CD122 on macrophages. Neither type I nor type II IFNs are required to generate CD122+Macs, however. In response to IL-15, CD122+Macs activate the ERK signaling cascade and enhance production of proinflammatory cytokines after stimulation with the TLR9 agonist CpG. Finally, we provide evidence of human cells that phenocopy murine CD122+Macs in secretory phase endometrium during the implantation window and in first-trimester uterine decidua. Our data support a model wherein IFNs local to the maternal-fetal interface direct novel IL-15-responsive macrophages with the potential to mediate IL-15 signals critical for optimal outcomes of pregnancy.

The Abundance and Availability of Cytokine Receptor IL-2Rß (CD122) Constrain the Lymphopenia-Induced Homeostatic Proliferation of Naive CD4 T Cells.

Lymphopenia-induced homeostatic proliferation (LIP) is a critical mechanism for restoring T cell immunity upon lymphodepleting insults or infections. LIP is primarily driven by homeostatic cytokines, such as IL-7 and IL-15, but not all T cells respond with the same efficiency to homeostatic proliferative cues. Although CD8 T cells vigorously proliferate under lymphopenic conditions, naive CD4 T cells are substantially impaired in their response to homeostatic cytokines, and they fail to fully expand. In this study, we show that the availability of IL-2Rß (CD122), which is a receptor subunit shared by IL-2 and IL-15, affects both the cytokine responsiveness and the LIP of naive CD4 T cells in the mouse. The enumeration of surface IL-2Rß molecules on murine naive CD4 and naive CD8 T cells revealed a 5-fold difference in IL-2Rß abundance. Notably, it was the limited availability of IL-2Rß that impaired CD4 T cell responsiveness to IL-15 and suppressed their LIP. As such, forced IL-2Rß expression on CD4 T cells by transgenesis bestowed IL-15 responsiveness onto naive CD4 T cells, which thus acquired the ability to undergo robust LIP. Collectively, these results identify IL-2Rß availability as a new regulatory mechanism to control cytokine responsiveness and the homeostatic proliferation of murine CD4 T cells.

Amniotic immune biomarkers as risk factors in women with different symptoms of threatened late miscarriage.

PROBLEM: To investigate risk factors that can help identify the possibility of pregnancy loss in threatened late miscarriage (TLM) patients with and without spontaneous uterine contractions. METHOD OF STUDY: Amniotic immune biomarkers (IL2ß receptor, IL6, IL8, IL10, IL1ß, and TNFα) were assayed, and "sludge" was assessed. Patients without intrauterine infections were treated and followed up until delivery, and pregnancy outcomes were recorded. The two groups were compared for the differences in biomarker levels and "sludge," and the independent associations of biomarkers, "sludge," and other maternal factors with late miscarriage were investigated. RESULTS: The amniotic levels of IL2ßR, IL8, and TNFα were higher in the group with contractions (P < .05). When considered alone, each of the six biomarkers was significantly associated with late miscarriage in the no-contractions group and four of these (IL8, IL10, IL1ß, and TNFα) in the contractions group (P < .05). Biomarker levels were correlated, and in multivariate Cox regression analysis, there was an independent effect only for IL8 in the no-contractions group (HR = 18.16, 95% CI: 5.75-57.43) and TNFα in the contractions group (HR = 4.11, 95% CI: 1.68-10.08). For patients with contractions, IL10, IL8, and IL1ß were different in those with and without "sludge," but no such difference was seen in the no-contractions group. CONCLUSION: For TLM patients without intrauterine infections, amniotic immune biomarkers differ between patients with different symptoms, not only for their levels but also for the impact of these biomarkers on the risk of late miscarriage. These findings suggest that the symptoms of TLM should be considered in the study of miscarriage risk.

Exercise training improves radiotherapy efficiency in a murine model of prostate cancer.

Engaging in exercise while undergoing radiotherapy (RT) has been reported to be safe and achievable. The impact of exercise training (ET) on RT efficiency is however largely unknown. Our study aims to investigate the interactions between ET and RT on prostate cancer growth. Athymic mice received a subcutaneous injection of PPC-1 cells and were randomly assigned to either cancer control, cancer ET, cancer RT, or cancer RT combined with ET (CaRT-ET). Mice were sacrificed 24 days post-injection. All three intervention groups had reduced tumor size, the most important decrease being observed in CaRT-ET mice. Apoptotic marker cleaved caspase-3 was not modified by ET, but enhanced with RT. Importantly, this increase was the highest when the two strategies were combined. Furthermore, NK1.1 staining and gene expression of natural killer (NK) cell receptors Klrk1 and Il2rß were not affected by ET alone but were increased with RT, this effect being potentiated when combined with ET. Overall, our study shows that (a) ET enhances RT efficiency by potentiating NK cell infiltration, and (b) while ET alone and ET combined with RT both reduce tumor growth, the mechanisms mediating these effects are different.

Single-cell RNA-sequencing identifies the developmental trajectory of C-Myc-dependent NK1.1- T-bet+ intraepithelial lymphocyte precursors.

Natural intraepithelial lymphocytes (IELs) are thymus-derived adaptive immune cells, which are important contributors to intestinal immune homeostasis. Similar to other innate-like T cells, they are induced in the thymus through high-avidity interaction that would otherwise lead to clonal deletion in conventional CD4 and CD8 T cells. By applying single-cell RNA-sequencing (scRNA-seq) on a heterogeneous population of thymic CD4-CD8αß-TCRαß+NK1.1- IEL precursors (NK1.1- IELPs), we define a developmental trajectory that can be tracked based on the sequential expression of CD122 and T-bet. Moreover, we identify the Id proteins Id2 and Id3 as a novel regulator of IELP development and show that all NK1.1- IELPs progress through a PD-1 stage that precedes the induction of T-bet. The transition from PD-1 to T-bet is regulated by the transcription factor C-Myc, which has far reaching effects on cell cycle, energy metabolism, and the translational machinery during IELP development. In summary, our results provide a high-resolution molecular framework for thymic IEL development of NK1.1- IELPs and deepen our understanding of this still elusive cell type.

A next-generation tumor-targeting IL-2 preferentially promotes tumor-infiltrating CD8+ T-cell response and effective tumor control.

While IL-2 can potently activate both NK and T cells, its short in vivo half-life, severe toxicity, and propensity to amplify Treg cells are major barriers that prevent IL-2 from being widely used for cancer therapy. In this study, we construct a recombinant IL-2 immunocytokine comprising a tumor-targeting antibody (Ab) and a super mutant IL-2 (sumIL-2) with decreased CD25 binding and increased CD122 binding. The Ab-sumIL2 significantly enhances antitumor activity through tumor targeting and specific binding to cytotoxic T lymphocytes (CTLs). We also observe that pre-existing CTLs within the tumor are sufficient and essential for sumIL-2 therapy. This next-generation IL-2 can also overcome targeted therapy-associated resistance. In addition, preoperative sumIL-2 treatment extends survival much longer than standard adjuvant therapy. Finally, Ab-sumIL2 overcomes resistance to immune checkpoint blockade through concurrent immunotherapies. Therefore, this next-generation IL-2 reduces toxicity while increasing TILs that potentiate combined cancer therapies.

Clinical trial of a humanized anti-IL-2/IL-15 receptor ß chain in HAM/TSP.

OBJECTIVE: Human T cell lymphotropic virus 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic, progressive, neurological disease. Chronic activation of CD8+ T cells, as evidenced by increased spontaneous lymphoproliferation and HTLV-1-specific cytotoxic T cells, has been demonstrated in HAM/TSP patients. Since IL-2 and IL-15 stimulate memory CD8+ T cell activity, these cytokines have been implicated in the immunopathogenesis of HAM/TSP. In this phase I trial, we evaluated the safety, pharmacokinetics, and ability of Hu-Mikß1, a humanized monoclonal antibody directed toward the IL-2/IL-15 receptor ß-chain (IL-2/IL-15Rß: CD122), to saturate CD122 and regulate abnormal immune responses in patients with HAM/TSP by inhibition of IL-15 action. METHODS: Hu-Mikß1 was administered intravenously at doses of 0.5 mg/kg, 1.0 mg/kg, or 1.5 mg/kg in a total of nine HAM/TSP patients. Five doses of Hu-Mikß1 were administered at 3-week intervals. The clinical response was evaluated using standardized scales. Viral and immunologic outcome measures were examined including HTLV-1 proviral load, T cell phenotypic analysis and spontaneous lymphoproliferation in HAM/TSP patients. RESULTS: There was no significant toxicity associated with Hu-Mikß1 administration in HAM/TSP patients. Saturation of CD122 by Hu-Mikß1 was achieved in five out of nine HAM/TSP patients. Administration of Hu-Mikß1 was associated with inhibition of aberrant CD8+ T cell function including spontaneous lymphoproliferation and degranulation and IFN-γ expression, especially in HAM/TSP patients that achieved CD122 saturation. INTERPRETATION: The treatment with Hu-Mikß1 had a number of immunological effects on HAM/TSP patients although no clinical efficacy was observed. We also did not see any dose-related toxicity.

IL7 receptor signaling in T cells: A mathematical modeling perspective.

Interleukin-7 (IL7) plays a nonredundant role in T cell survival and homeostasis, which is illustrated in the severe T cell lymphopenia of IL7-deficient mice, or demonstrated in animals or humans that lack expression of either the IL7Rα or γ c chain, the two subunits that constitute the functional IL7 receptor. Remarkably, IL7 is not expressed by T cells themselves, but produced in limited amounts by radio-resistant stromal cells. Thus, T cells need to constantly compete for IL7 to survive. How T cells maintain homeostasis and further maximize the size of the peripheral T cell pool in face of such competition are important questions that have fascinated both immunologists and mathematicians for a long time. Exceptionally, IL7 downregulates expression of its own receptor, so that IL7-signaled T cells do not consume extracellular IL7, and thus, the remaining extracellular IL7 can be shared among unsignaled T cells. Such an altruistic behavior of the IL7Rα chain is quite unique among members of the γ c cytokine receptor family. However, the consequences of this altruistic signaling behavior at the molecular, single cell and population levels are less well understood and require further investigation. In this regard, mathematical modeling of how a limited resource can be shared, while maintaining the clonal diversity of the T cell pool, can help decipher the molecular or cellular mechanisms that regulate T cell homeostasis. Thus, the current review aims to provide a mathematical modeling perspective of IL7-dependent T cell homeostasis at the molecular, cellular and population levels, in the context of recent advances in our understanding of the IL7 biology. This article is categorized under: Models of Systems Properties and Processes > Organ, Tissue, and Physiological Models Biological Mechanisms > Cell Signaling Models of Systems Properties and Processes > Mechanistic Models Analytical and Computational Methods > Computational Methods.